Respiration in Plants — Page 3 | NEET Biology

Q21

During which stage in complete oxidation of glucose are the greatest number of ATP molecules formed?

A glycolysis

B Krebs cycle

C conversion of pyruvic acid to acetyl CoA

D electron transport chain

Correct Answer

Option D

Solution

(d) ETS (electron transport chain) produces the majority of ATP via oxidative phosphorylation.

Q22

Chemiosmotic theory of ATP synthesis in chloroplasts and mitochondria is based on

A membrane potential

B accumulation of Na ions

C accumulation of K ions

D proton gradient

Correct Answer

Option D

Solution

(d) Mitchell's chemiosmotic theory: proton gradient (not ion gradient) drives ATP synthesis.

Q23

The overall goal of glycolysis, Krebs cycle and ETS is the formation of

A ATP in one large oxidation reaction

B sugars

C nucleic acids

D ATP in small stepwise units

Correct Answer

Option D

Solution

(d) Cellular respiration produces ATP in small stepwise units through coupled reactions.

Q24

All enzymes of TCA cycle are in mitochondrial matrix except succinate dehydrogenase which is located in

A isocitrate dehydrogenase

B malate dehydrogenase

C succinate dehydrogenase

D lactate dehydrogenase

Correct Answer

Option C

Solution

(c) Succinate dehydrogenase is embedded in the inner mitochondrial membrane (part of Complex II/ETS).

Q25

The chemiosmotic coupling hypothesis proposes that ATP is formed because

A high energy bonds are formed in mitochondrial proteins

B ADP is pumped out of the matrix into intermembrane space

C a proton gradient forms across the inner membrane

D there is a change in permeability of the inner mitochondrial membrane toward ADP

Correct Answer

Option C

Solution

(c) Mitchell's chemiosmotic theory: proton gradient across inner mitochondrial membrane drives ATP synthase.

Q26

Which statement is wrong for Krebs cycle?

A There is one point in the cycle where FAD+ is reduced to FADH2

B During conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised

C The cycle starts with condensation of acetyl CoA with pyruvic acid to yield citric acid

D There are three points in the cycle where NAD+ is reduced to NADH+H+

Correct Answer

Option C

Solution

(c) Krebs cycle starts with condensation of acetyl CoA (2C) with oxaloacetate (4C) — not pyruvic acid.

Q27

Conversion of glucose to glucose-6-phosphate (first irreversible reaction of glycolysis) is catalysed by

A Aldolase

B Hexokinase

C Enolase

D Phosphofructokinase

Correct Answer

Option B

Solution

(b) Hexokinase catalyses the first step of glycolysis — phosphorylation of glucose to glucose-6-phosphate.

Q28

Incomplete oxidation of glucose into pyruvic acid through several steps is known as

A TCA-pathway

B glycolysis

C HMS-pathway

D Krebs cycle

Correct Answer

Option B

Solution

(b) Glycolysis (EMP pathway): partial oxidation of glucose to pyruvate.

Q29

EMP pathway can produce a total of

A 6 ATP

B 8 ATP

C 24 ATP

D 38 ATP

Correct Answer

Option B

Solution

(b) Glycolysis: 2 ATP (substrate level) + 2 NADH × 3 ATP = 8 ATP total.

Q30

End product of glycolysis is

A acetyl CoA

B pyruvic acid

C glucose 1-phosphate

D fructose 1-phosphate

Correct Answer

Option B

Solution

(b) Pyruvic acid (pyruvate) is the 3-carbon end product of glycolysis.